How the Amount of Sugar can Affect Activity of Yeast

Yeast feeds on sugar so by adding a tablespoon or two provides yeast a readily available food.  This increases yeast’s activity and speeds up fermentation as well. However, adding a large amount of sugar to your dough will affect yeast’s metabolism.  Sugar is hygroscopic which  means it absorbs moisture from the dough.  Therefore, it decreases the amount of water needed by yeast to hydrate and breakdown the complex starch molecules in flour.